Dream reports are to be collected on laboratory awakenings from REM sleep, NREM sleep, and sleep onset; subjects later associate to these reports, as well as to reported spontaneous waking mentation. As analyzed by Scoring System for Latent Structure (Foulkes, A Grammar of Dreams, 1978), the associative and dream data will permit: modelling of the associative sources of nocturnal mentation; modelling of the transformations which these sources undergo in dream formation; comparisons of dream constructional processes in different sleep stages; and contrast of the associative mechanisms underlying waking and sleeping thought. Subjects already studied include blind persons and sighted controls; subjects to be studied are patients with such thought disorder and appropriately matched controls. For correlational purposes, comprehensive waking cognitive profiles are obtained for each subject. Subjects serve for 8-week periods: each week, there is one night of dream collection, one association period, and one waking test session.